Spark Plug Set, Denso Iridium IT20, for 90~95 ZR-1 LT5. These are Iridium, tapered seat plugs.  Iridium is the performance standard of today's automotive industry. 

NOTE: All LT5 engines were machined to accept spark plugs using either flat washer seals or tapered seat plugs.  1990~92 LT5 engines employed the flat seal washer, whereas 1993~95 engines used tapered seat spark plugs.  Tapered seat plugs can be used in 90~92 engines, requiring only seating the plugs slightly tighter than normal to create a matching, seal surface in the cylinder head.  Loosen and re-tighten the spark plug to standard torque specification.  

Sold as a set of 8.